Reamer tool

ABSTRACT

A reamer tool which is capable of removing paraffin scale, ice, salt, calcium, cement, barium and other accumulations from the inside surfaces of oil well pump tubing and casing, which reamer tool may include a housing for suspension in the well tubing or casing; a shaft slidably mounted in the housing for attachment to an impact device; shaft threads provided on the shaft; a lock nut threadibly mounted on the shaft for removably engaging the housing; and a reset spring provided in the housing between the housing and the end of the shaft. Displacement of the shaft in the housing causes the lock nut to engage the housing, and the lock nut rotates on the shaft threads and rotates the housing such that the housing rotates in the well bore or casing and removes the solid blockages from the well bore or casing.

BACKGROUND OF THE INVENTION Field of the Invention

[0001] This invention relates to oil well cleaning apparatus, and more particularly, to a reamer tool which can be used for scraping and removing paraffin, scale, ice, barium cement, salt, calcium and other accumulations from the inside surfaces of oil well tubing and casing. The tool can easily be adapted for use with a snubbing unit, cable rig, coiled tubing, cable, or electric wireline in an oil or gas well. The reamer tool may be operated in cooperation with a wire line typically fitted with a swivel joint, and with a load applicator such as one or more spanner jars, for alternately applying a repetitive impact load to the tool and sequentially repositioning the tool for further load application.

[0002] The problem of restricted flow of hydrocarbons in oil wells due to the accumulation of paraffin and other deposits on the inside wall of the tubing is one of great concern in the oil field. Paraffin accumulation sometimes occurs in a relatively short period of time and can form a tough, semi-solid deposit which severely restricts the flow of fluid in the tubing. Accumulation thickness and character vary with the type and quantity of oil and hydrocarbon fluid produced, and frequently causes severe stress in pumping apparatus and equipment, with resulting equipment failure or low operating efficiency. Typically, the accumulation of paraffin deposits in oil well production tubing occurs at a point where the hydrostatic pressures and temperatures create favorable conditions for precipitation of solid paraffin from the oil. Other deposits such as rust, scale, salt, calcium cement, barium and ice must frequently be removed from production tubing and casing, particularly in corrosive environments, and in the case of ice, in regions characterized by prolonged low temperature.

[0003] Paraffin and other deposit accumulations in production tubing are frequently removed by using expensive and sometimes complicated scraping tools which may be attached to the sucker rods deployed in the well This technique is time-consuming and expensive since the sucker rod string must first be removed, the paraffin scraper tool or tools then installed on the sucker rods, the rods and accompanying scraping tools reinserted in the well, the scraping operation completed, and the tools finally removed. Such a procedure can be prohibitively expensive in some wells and impractical in others, and the tools sometimes break and become jammed in the tubing. Furthermore, the accumulation of paraffin and asphalt in the tubing sometimes becomes too thick for removal by application of such equipment, and the tubing string must then be pulled out of the well and “burned” in order to remove the accumulated deposits. This procedure is extremely time-consuming and expensive, and is normally used only as a last resort when conventional tools cannot be used effectively. Further, while tools which have become inadvertently stuck or jammed in the well bore or casing can be jarred loose and removed easily and inexpensively in most cases, sometimes it is necessary to apply rotational force to the jammed tool in order to dislodge and remove the the tool from the well bore or casing.

[0004] Another technique frequently used to remove accumulated deposits from well tubing includes pulling and disconnecting a sufficient number of sucker rods to facilitate insertion of a “hook and washer” type cleaning tool to the point of deposit accumulation, and subsequently pulling the tool out of the tubing to scrape the deposit loose. This technique is also time-consuming, and is relatively inefficient and expensive.

[0005] Accordingly, an object of this invention is to provide a reamer tool which can be used to remove deposits and accumulations of paraffin, asphalt, scale, ice, salt, calcium, barium, cement and other materials from the inside surfaces of oil well tubing and casing.

[0006] Another object of the invention is to provide a reamer tool which can be lowered into a well tubing or casing and repetitively loaded to clear the tubing and casing.

[0007] Yet another object of this invention is to provide a casing and tubing reamer tool which is capable of cleaning deposits in well tubing and casing, which reamer includes a housing and a threaded shaft slidably displaceable in the housing, such that sliding of the shaft in the housing rotates the housing.

[0008] A still further object of this invention is to provide a reamer tool which is capable of cleaning deposits in well tubing and casing, which reamer tool includes a housing capable of suspension in the well tubing or casing; a shaft slidably mounted in the housing; shaft threads provided on the shaft; a lock nut threadibly mounted on the shaft for removably engaging the housing; and a reset spring provided in the housing between the housing and the end of the shaft, such that displacement of the shaft in the housing causes the lock nut to engage the housing, and the lock nut rotates on the shaft threads and rotates the housing such that the housing rotates in the well bore or casing and removes paraffin, scale, ice, salt, calcium, cement, barium or other solid blockages from the well bore or casing.

[0009] Yet another object of the invention is to provide a reamer tool for insertion in oil field casing and tubing, which reamer tool is capable of being adapted to run fishing tools in addition to removing accumulations of paraffin, scale, ice, cement, salt, calcium, barium and other material from the tubing and casing of oil and gas wells.

[0010] Another object of this invention is to provide a reamer tool which can be easily adapted to and used on virtually any type of conventional oil or gas service application, including snubbing units and cable rigs, coiled tubing, drill string, cable, or electric wireline.

[0011] Yet another object of this invention is to provide a reamer tool which can be adapted with a cutlip guide to facilitate maneuvering tubing, cable, electric wireline or other objects to the center of well casing, or adapted with an overshot to facilitate dislodging and removing immobilized or inadvertently released downhole tools from the well bore or casing.

[0012] A still further object of this invention is to provide a reamer tool which can be used to penetrate tight segments of a well bore and is capable of extension through downhole valves for clearing the valves.

SUMMARY OF THE INVENTION

[0013] These and other objects of the invention are provided in a reamer tool which is capable of removing paraffin, scale, ice, salt, calcium, cement, barium and other accumulations from the inside surfaces of oil well pump tubing and casing and can easily be adapted for use with coiled tubing, cable or electric wireline, which reamer tool may include a housing for suspension in the well tubing or casing; a shaft slidably mounted in the housing; shaft threads provided on the shaft; a lock nut threadibly mounted on the shaft for removably engaging the housing; and a reset spring provided in the housing between the housing and the end of the shaft, such that displacement of the shaft in the housing causes the lock nut to engage the housing, rotate on the shaft threads and rotate the housing such that the housing rotates in the well bore or casing and removes paraffin, scale, ice, salt, calcium cement, barium or other solid blockages from the well bore or casing. The reamer tool can be fitted with an overshot to facilitate dislodging and removing downhole tools or other immobilized or inadvertently released objects from the well bore or casing, or with a cutlip guide to facilitate maneuvering downhole objects to the center of the well bore or casing, as needed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The invention will be better understood by reference to the accompanying drawings, wherein:

[0015]FIG. 1 is a perspective, partially exploded view of an illustrative embodiment of the reamer tool of this invention;

[0016]FIG. 2 is a side view of the reamer tool illustrated in FIG. 1, with the shaft partially extended from the housing;

[0017]FIG. 3 is a sectional view taken along lines 3-3 in FIG. 1, more particularly illustrating the reamer tool with the shaft in retracted configuration in the housing;

[0018]FIG. 4 is a sectional view, also taken along 3-3 in FIG. 1, of the reamer tool, more particularly illustrating the shaft partially extended from the housing;

[0019]FIG. 5 is an exploded, perspective view, partially in section, of the reamer tool;

[0020]FIG. 6 is a front or rear view of the lock nut component of the reamer tool;

[0021]FIG. 7 is a longitudinal sectional view of the lock nut illustrated in FIG. 6;

[0022]FIG. 8 is a longitudinal sectional view of another illustrative embodiment of the reamer tool of this invention;

[0023]FIG. 9 is a bottom view of the lock nut illustrated in FIG. 6;

[0024]FIG. 10 is a longitudinal sectional view of a blade base component of the reamer tool of this invention, in an illustrative application of the reamer tool; and

[0025]FIG. 11 is a side view of the reamer tool, with the blade base of FIG. 10 mounted on the reamer tool.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Referring initially to FIGS. 1, 2 and 5 of the drawings, an illustrative embodiment of the reamer tool of this invention is generally illustrated by reference numeral 1. The reamer tool 1 typically includes an elongated housing 19 having a top housing section 2, a middle housing section 3 and a bottom housing section 4, which are removably attached to each other, respectively, by means of cooperating threads, as hereinafter described. Removal of the top housing section 2 from the middle housing section 3 and the middle housing section 3 from the bottom housing section 4, respectively, is typically achieved by applying a wrench (not illustrated) to wrench flats 13, to unscrew the respective housing sections and disassemble the reamer 1. Typically, as illustrated in FIG. 1, top housing internal threads 5 of the top housing section 2 receive upper external threads 9 of the middle housing section 3, and lower external threads 9 a of the middle housing section 3 receive interior bottom housing threads 11 (FIG. 5) of the bottom housing section 4 in assembly of the housing 19. The top housing section 2 is typically additionally secured to the middle housing section 3 by means of housing set screws 14, which are threaded in respective top housing set screw apertures 15, as illustrated in FIG. 5. Similarly, the middle housing section 3 is typically further secured to the bottom housing section 4 by means of additional set screws 14, which are threaded in respective bottom housing set screw apertures 17. The top housing section 2 is further typically provided with a top housing collar 7, which is capped by a top housing fishing flange 8, provided with a top housing flange aperture 36 that opens the top housing section 2, as illustrated in FIG. 5. Similarly, the middle housing section 3 is provided with a middle housing aperture 37 at the top thereof, and is further provided with a middle housing shoulder 21 for receiving the bottom edge of the top housing section 2.

[0027] Referring next to FIGS. 3-5 of the drawings, a shaft 25, provided with course, double-lead shaft threads 29 and an upper, polished shaft segment 25 a, is inserted in the top housing flange aperture 36 (FIG. 5) of the top housing fishing flange 8. As particularly illustrated in FIGS. 3 and 4, the polished shaft segment 25 a of the shaft 25 projects through the top housing flange aperture 36 (FIG. 5), through the top housing collar 7 and into the top housing cavity 12 in the interior of the top housing section 2, and through the middle housing aperture 37 into the middle housing cavity 18 of the middle housing section 3, as illustrated in FIG. 3. The shaft 25 further extends into a spring cavity 6 of the bottom housing section 4, as illustrated in FIG. 3. The shaft 25 is further provided with connector threads 26 at the upper end thereof for cooperating with a wire line apparatus (not illustrated), and is provided with a connector flange 27, located immediately beneath the connector threads 26. As illustrated in FIG. 5, the opposite end of the shaft 25 is fitted with shaft threads 34, in order to accommodate a circular shaft nut 30, provided with central interior nut threads 31. It will be appreciated by those skilled in the art that the shaft threads 34 are typically provided on the shaft 25 in the same direction as the shaft threads 29, and the shaft nut 30 is threaded to fit on the shaft threads 34. One or more set screws 14 may be threaded through respective shaft nut set screw apertures 30 a to engage the shaft threads 34 (FIG. 5) of the shaft 25 and further secure the shaft nut 30 on the shaft threads 34. Alternatively, it is understood that the shaft nut 30 can be characterized by a conventional, self-locking, plastic-coated nut which is adapted for mounting on the shaft 25 according to the knowledge of those skilled in the art. The shaft 25 is maintained in essentially vertical configuration inside the housing 19 by means of the top housing collar 7. As illustrated in FIGS. 3 and 4, a thrust washer 22 is typically provided in the top housing cavity 12, against the top housing collar 7, and encircles the shaft 25. A lock nut 38, provided with a pair of downwardly-extending lock nut lugs 39, is fitted with internal lock nut threads 40, as illustrated in FIG. 7, and is situated in the top housing cavity 12 for threadible cooperation with the shaft threads 29 of the shaft 25. The lock nut 38 is free to rotatably traverse the shaft threads 29 on the shaft 25 inside the top housing cavity 12, responsive to movement of the shaft 25 between a fully extended configuration from the housing 19, as illustrated in FIG. 4, and the retracted position in the housing 19, shown in FIG. 3. A lock nut lug seat 42 is provided in the top housing cavity 12 at the top end of the middle housing section 3, and is fitted with at least two lug seat slots 43, which are typically shaped to define lug seat bevels 44, as more particularly illustrated in FIG. 5. The lug seat slots 43 are designed to receive the respective, downwardly-extending lock nut lugs 39 of the lock nut 38 when the lock nut 38 is seated on the lock nut lug seat 42, as the shaft 25 is forced downwardly through top housing collar 7, the top housing cavity 12 and the middle housing cavity 18 by operation of a downward load applied to the shaft 25. The lug seat slots 43 may be slightly deeper than the length of the lock nut lugs 39, in order to allow the lock nut 38 to contact the lock nut lug seat 42. As illustrated in FIGS. 3-5 of the drawings, the depth of retraction or closing of the shaft 25 inside the housing 19 is limited by the shaft fishing flange 28, provided on the shaft 25, as illustrated. The shaft fishing flange 28 is typically formed integrally with the shaft 25 for maximum strength. As further illustrated in FIGS. 3 and 4, a wiper ring 32 and an o-ring 33, seated in respective grooves provided in the top housing collar 7 of the top housing section 2, encircle the polished shaft segment 25 a of the shaft 25 for wiping and sealing, respectively, the polished shaft segment 25 a as the shaft 25 reciprocates in the top housing collar 7, which wiper ring 32 maintains the polished shaft segment 25 a free from dirt and other contaminants and thus, prevents locking or sticking of the shaft 25 in the top housing collar 7.

[0028] Referring next to FIGS. 3-5 of the drawings, the bottom housing section 4 of the housing 19 is characterized by an internal spring cavity 6, which communicates with a typically smaller-diameter bottom sucker rod receptacle 4 a, provided with interior receptacle threads 4 b. A coiled reset spring 16 is fitted in the spring cavity 6, and rests against an annular spring shoulder 6 a of the bottom housing 4, between the spring cavity 6 and the sucker rod receptacle 4 a. As illustrated in FIGS. 3 and 4, the shaft nut 30, provided on the bottom end of the shaft 25, impinges against the reset spring 16, and the reset spring 16 is compressed between the shaft nut 30 and the spring shoulder 6 a when the shaft 25 is disposed in the retracted configuration in the housing 19 as illustrated in FIG. 3. Conversely, the reset spring 16 is in the extended configuration in the spring cavity 6 when the shaft 25 is in the fully extended configuration from the housing 19, as illustrated in FIG. 4, the purpose of which reset spring 16 will be hereinafter described. In one application of the reamer 1, the sucker rod receptacle 4 a is capable of receiving the threaded male element (not illustrated) on the upper end of a sucker rod (not illustrated) in the well bore or tubing for loosening the sucker rod in the event that the sucker rod inadvertently becomes immobilized in the tubing, as hereinafter described.

[0029] Referring next to FIGS. 10 and 11 of the drawings, a blade base 45, such as that described in my U.S. Pat. No. 4,452,307, can be mounted on the bottom housing section 4 of the reamer tool 1 to facilitate cleaning paraffin, scale, ice, salt, calcium, cement, barium or other material from a length or section of tubing or casing (not illustrated), as hereinafter described. The blade base 45 is tapered and, as illustrated in FIG. 10, includes a threaded base nipple 48 that threadibly engages the receptacle threads 4 b (FIG. 3) of the bottom housing section 4, in the sucker rod receptacle 4 a thereof. Multiple set screws 14 threaded into respective set screw apertures (not illustrated) provided in the bottom housing 4 are typically caused to engage the base nipple 48 and further secure the blade base 45 on the bottom housing section 4. As illustrated in FIG. 11, the blade base 45 is typically provided with multiple, parallel longitudinal blade slots 46, each of which receives and mounts a corresponding blade 47 which is typically heat-treated for maximum hardness and strength and configured to define a blade head 49 that mates with a base blade support 6 at the lower, tapered end of the blade base 45. The blades 47 are typically removably mounted in the respective blade slots 46 by means of multiple blade bolts (not illustrated).

[0030] Referring again to the drawings, in typical operation, a reamer tool 1 having a shaft 25 fitted with left-handed shaft threads 29, is utilized to clean a length or section of tubing or casing (not illustrated), as follows. One or more spanner jars (not illustrated) are threadibly connected to the connector threads 26 of the shaft 25, and a wire line (not illustrated) having a conventional swivel joint (not illustrated) is attached to the opposite end of the spanner jar string. The reamer tool 1 is then lifted by means of the wire line into position for insertion in the tubing or casing such that the weight of the housing 19, in combination with the upward biasing effect of the reset spring 16 against the shaft 25, facilitates fill extension of the shaft 25 from the housing 19, as illustrated in FIG. 4. At this point the lock nut 38, supported on the shaft 25 by means of the shaft threads 29, is initially in the uppermost position in the top housing cavity 12, against the thrust washer 22. The lock nut 38 then rotates on the shaft 25 as it downwardly traverses the shaft threads 29 by pull of gravity, until the lock nut lugs 39 of the lock nut 38 engage the lock nut lug seats 42 of the housing 19. The reamer tool 1, spanner jar or jars, and wire line are then lowered into the casing or tubing string until the reamer tool 1 is prevented from further penetration by an accumulation or deposit of paraffin, scale, ice, salt, calcium, cement, barium or other material in the casing or tubing string. At this point, the wire line and spanner jar assembly are lifted in conventional fashion until the spanner jars are raised to maximum position above the reamer tool 1, after which the spanner jars are allowed to drop and impact on the connector flange 27 of the shaft 25. This impact initially causes the shaft 25 to downwardly traverse the top housing cavity 12 of the top housing section 2 and non-rotatably extend downwardly through the lock nut 38, whereupon the lock nut 38, engaging the middle housing section 3 at the lock nut lug seats 42, rotatably traverses the shaft threads 29 of the downwardly-moving and non-rotating shaft 25. This clockwise rotation of the lock nut 38 on the shaft threads 29 effects clockwise rotation of the housing 19 and attached blade base 45 with the lock nut 38 on the non-rotating and downwardly-moving shaft 25, when a shaft 25 and lock nut 38 having cooperating left-hand threads are used in the reamer 1. This rotating action of the housing 19 and blade base 45, imparted by the rotating lock nut 38, effects removal of the deposits which are adjacent to the blades 47 due to the rotation of the blade base 45 and blades 47. After the initial impact between the spanner jar or jars and the connector flange 27 of the shaft 25, the spanner jar assembly is again lifted by means of the wire line, and is again caused to impact on the connector flange 27, thus effecting additional rotation of the reamer tool 1 and additional contact between the blades 47 and the accumulated deposits to effect additional removal of the deposits. This repetitive 1 and dropping of the spanner jar or jars to achieve impact between the spanner jar system and the connector flange 27 on the shaft 25 is continued until the shaft fishing flange 28 contacts the top housing fishing flange 8, as illustrated in FIG. 3 of the drawings. When this configuration of the reamer tool 1 is realized, the wire line is again placed in tension and the spanner jar or jars are lifted. Accordingly, the shaft 25 is again displaced from its retracted position in the top housing section 2 and the middle housing section 3, as the lock nut lugs 39 disengage the lug seat slots 43 and the lock nut 38 is displaced upwardly with the shaft 25 in the top housing cavity 12. Upward movement of the shaft 25 in the top housing cavity 12 and through the top housing collar 7 is assisted by the reset spring 16, which impinges against the shaft nut 30 and tends to reset the original position of the shaft 25 and the lock nut 38 in the top housing cavity 12. It will be appreciated from a consideration of FIGS. 3 and 4 of the drawings that when the shaft 25 is extended from the housing 19 as illustrated in FIG. 4, the lock nut 38 is initially and transiently raised against the thrust washer 22 inside the top housing collar 7 and then rotates as it downwardly traverses the shaft threads 29 by pull of gravity. At that point, the lock nut lugs 39 of the lock nut 38 engage the lock nut lug seats 42 of the housing 19 prior to non-rotating, downward movement of the shaft 25 through the top housing cavity 12 and the lock nut 38, as heretofore described. Any rotation of the shaft 25 with respect to the wire line is handled by means of the swivel joint, which attaches the wire line to the spanner jar system, in order to prevent the wire line from twisting.

[0031] It is understood that a shaft 25 having right-handed shaft threads 29 and a cooperating lock nut 38 can be installed in the reamer tool 1 to replace the shaft 25 and lock nut 38 having left-handed threads, as heretofore described. This replacement causes the housing 19 to rotate in a counter-clockwise direction when the reamer tool 1 is operated as described above.

[0032] It will be further understood that the reamer tool 1 of this invention can also function as a fishing tool runner by removing the blade base 45 from the bottom housing section 4 to expose the sucker rod receptacle 4 a to receive an “overshot” having a male fitting adapted for threadible cooperation with the sucker rod receptacle 4 a. A wire line and fishing tool (not illustrated) can be suspended from the overshot to effect fishing operations, and the rotational motion of the reamer tool 1 responsive to hammer jar impact can be used to free immobilized tubing, casing, tools and the like, in the hole. It is also understood that a conventional bailer (not illustrated) can be attached to the sucker rod receptacle 4 a to facilitate cutting salt, calcium, cement, barium, paraffin, ice, scale or other accumulations and removing the accumulations from the well bore in a single operation.

[0033] It will be appreciated by those skilled in the art that the reamer tool 1 of this invention can perform many of the functions which otherwise require high-cost equipment, at a fraction of the cost and time. The reamer tool 1 is capable of cutting and removing virtually any type of accumulation or deposit in an oil well tubing and casing, including salt, calcium, cement, barium, hard paraffin, ice plugs, scale and asphalt, in non-exclusive particular. Additionally, by fitting a conventional bailer (not illustrated) on the reamer tool 1, as heretofore described, both the cutting and bailing functions of the reamer tool 1 can be performed at the same time, thus significantly decreasing the time required for the cutting and excavating operations. By fitting the reamer tool 1 with the blade base 45 (FIG. 11), the reamer tool 1 can be used to penetrate tight segments or areas in tubing string or well casing. A cutlip guide (not illustrated) can be fitted on the bottom end of the reamer tool 1 for maneuvering downhole tools or other objects to the center of the well bore or casing by operation of the reamer tool 1. The reamer tool 1 can be adapted to and used on virtually any type of ice application, including coiled tubing, snubbing units, cable rigs and electric wirelines, in non-exclusive particular, and can further be used to clear downhole valves clogged with deposit accumulations.

[0034] Referring next to FIG. 8 of the drawings, in another embodiment of the reamer tool, generally illustrated by reference numeral 62, the lock nut 38 has multiple lock nut lugs 39 which are upwardly-extending from the lock nut 38 in the top housing cavity 12. Accordingly, multiple, congruent lock nut lug seats 42, each having a lug seat bevel 44 (FIG. 5) and separated by lug seat slots 43 (FIG. 5), extend downwardly from the top housing section 2, into the top housing cavity 12 and above the upwardly-extending lock nut lugs 39 of the lock nut 38. A thrust washer 22 is typically seated on a washer seat 3 a inside the top housing cavity 12. Accordingly, the lock nut 38, engaging the shaftthreads 29 of the shaft 25, is situated to travel downwardly through the top housing cavity 12 with the shaft 25 upon application of a repetitive impact load to the connector flange 27 of the shaft 25, until the lock nut 38 engages the thrust washer 22. Upon subsequent upward pressure applied to the shaft 25 by operation of the wire line (not illustrated, attached to the connector threads 26 of the shaft 25), the shaft 25, assisted by the compressed reset spring 16, initially moves upwardly with respect to the housing 19, through the middle housing cavity 18, top housing cavity 12 and top housing collar 7. The lock nut 38 travels upwardly with the shaft 25 through the top housing cavity 12, until the lock nut lugs 39 of the lock nut 38 register with and are seated in the respective lock nut lug seats 42 of the top housing section 2. Continued upward and non-rotating movement of the shaft 25 through the top housing collar 7 causes the shaft threads 29 to progressively engage and rotate the interior lock nut threads 40 (FIG. 7) of the lock nut 38 and facilitate rotation of the lock nut 38 on the shaft 25 and consequently, rotation of the housing 19. Accordingly, the reamer tool 62 can be used to dislodge and remove a sucker rod (not illustrated) threadibly attached to the reamer tool 62 at the sucker rod receptacle 4 a of the bottom housing section 4 of the housing 19, for example. After full extension of the shaft 25 from the housing 19, the spanner jar assembly (not illustrated) is again lifted by means of the wire line, and is again caused to impact on the connector flange 27, thus effecting additional rotation of the housing 19 upon removal of the inpact load from the connector flange 27, as needed.

[0035] Referring again to FIGS. 3, 4 and 8 of the drawings, the pitch of the shaft threads 29 is ½ inch under circumstances where the shaft threads 29 are doublelead threads. The term “double-lead” is used to characterize shaft threads 29 which begin at points on the shaft 25 which are 180 degrees apart. The double-lead shaft threads 29 serve to more efficiently permit the lock nut 38 to freely rotate inside the top housing cavity 12 when the shaft 25 is displaced in the reamer housing 19 and the lock nut lugs 39 engage the lug seat slots 43, to rotate the reamer housing 19. It is understood that the shaft threads 29 of the shaft 25 and the lock nut threads 40 of the lock nut 38 can be either right-handed or left-handed, depending on the desired direction of rotation of the reamer housing 19 during application of the reamer tool 1. For example, when the shaft threads 29 of the shaft 25 and the lock nut threads 40 of the lock nut 38 are right-handed, the reamer housing 19 of the reamer tool 1 illustrated in FIGS. 3 and 4 rotates in the counterclockwise direction upon downward movement of the shaft 25 in the reamer housing 19, whereas the reamer housing 19 of the reamer tool 62 illustrated in FIG. 8 rotates in the clockwise direction upon upward movement of the shaft 25 in the reamer housing 19. Conversely, when the shaft threads 29 of the shaft 25 and the lock nut threads 40 of the lock nut 38 are left-handed, the reamer housing 19 of the reamer 1 illustrated in FIGS. 3 and 4 rotates in the clockwise direction upon downward movement of the shaft 25 in the reamer housing 19, whereas the reamer housing 19 of the reamer tool 62 illustrated in FIG. 8 rotates in the counterclockwise direction upon upward movement of the shaft 25 in the reamer housing 19. Therefore, depending upon the desired application, the reamer housing 19 of the reamer tool 1 illustrated in FIGS. 3 and 4 can be adapted to rotate downwardly in the clockwise direction or downwardly in the counterclockwise direction, depending upon whether the shaft threads 29 are left-handed or right-handed, respectively, whereas the reamer housing 19 of the reamer tool 62 illustrated in FIG. 8 can be adapted to rotate upwardly in the clockwise direction or upwardly in the counterclockwise direction, depending upon whether the shaft threads 29 are right-handed or left-handed, respectively.

[0036] While the preferred embodiments of the invention have been described above, it will be recognized and understood that various modifications can be made in the invention and the appended claims are intended to cover all such modifications which may fall within the spirit and scope of the invention. 

Having described my invention with the particularity set forth above, what is claimed is:
 1. A reamer for use with an impact device in oil well tubing and casing, said reamer comprising: a housing; an elongated shaft slidably disposed between a first position and a second position in said housing, said shaft having shaft threads; a lock nut threadibly engaging said shaft threads on said shaft for removably engaging said housing; a reset spring provided in said housing adjacent to said shaft for biasing said shaft in said first position; wherein said lock nut engages said housing, said shaft is rotatably stationary in said housing, said lock nut rotates on said shaft and said lock nut rotates said housing as said shaft is slidably displaced in a first direction between said first position and said second position in said housing by operation of the impact device; and wherein said lock nut disengages said housing and rotation of said housing is terminated as said shaft is slidably displaced in a second direction between said first position and said second position in said housing by operation of the impact device.
 2. The reamer of claim 1 comprising a plurality of lock nut lug seats provided on said housing and a plurality of lock nut lugs provided on said lock nut for removably engaging said plurality of lock nut lug seats, respectively.
 3. The reamer of claim 1 wherein said housing comprises a top housing section, a middle housing section attached to said top housing section and a bottom housing section attached to said middle housing section.
 4. The reamer of claim 3 comprising a plurality of lock nut lug seats provided on said housing and a plurality of lock nut lugs provided on said lock nut for removably engaging said plurality of lock nut lug seats, respectively.
 5. The reamer of claim 1 comprising a shaft nut provided on said shaft for engaging said reset spring.
 6. The reamer of claim 5 comprising a plurality of lock nut lug seats provided on said housing and a plurality of lock nut lugs provided on said lock nut for removably engaging said plurality of lock nut lug seats, respectively.
 7. The reamer of claim 5 wherein said housing comprises a top housing section, a middle housing section attached to said top housing section and a bottom housing section attached to said middle housing section.
 8. The reamer of claim 7 comprising a plurality of lock nut lug seats provided on said housing and a plurality of lock nut lugs provided on said lock nut for removably engaging said plurality of lock nut lug seats, respectively.
 9. A reamer for use with a wire line and impact device in oil well tubing and casing, said reamer comprising: a housing having an upper housing end and a lower housing end; a plurality of lock nut lug seats provided in said housing between said upper housing end and said lower housing end; an elongated shaft slidably disposed in said housing, said shaft having an upper shaft end for attachment to the wire line, a lower shaft end spaced from said upper shaft end and shaft threads between said lower shaft end and said upper shaft end; a lock nut threadibly engaging said shaft threads above said plurality of lock nut lug seats, said lock nut having a plurality of lock nut lugs for removably engaging said plurality of lock nut lug seats, respectively; a reset spring provided in said housing, said reset spring interposed between said housing and said lower shaft end of said shaft; wherein said shaft is slidably and non-rotatably displaced downwardly against said reset spring in said housing, said lock nut lugs of said lock nut engage said lock nut lug seats of said housing, said lock nut rotates on said shaft, and said lock nut rotates said housing when a load is applied to said shaft by operation of the impact device; and wherein said reset spring slidably displaces said shaft upwardly in said housing, said lock nut lugs of said lock nut disengage said lock nut lug seats of said housing, and rotation of said housing is terminated when the load is removed from the shaft by operation of the impact device.
 10. The reamer of claim 9 comprising a wiper ring provided in said housing and encircling said shaft for cleaning said shaft.
 11. The reamer of claim 9 wherein said housing comprises a top housing section, a middle housing section attached to said top housing section and a bottom housing section attached to said middle housing section.
 12. The reamer of claim 11 comprising a wiper ring provided in said housing and encircling said shaft for cleaning said shaft.
 13. The reamer of claim 9 comprising a shaft nut provided on said shaft for engaging said reset spring.
 14. The reamer of claim 13 comprising a wiper ring provided in said housing and encircling said shaft for cleaning said shaft.
 15. The reamer of claim 13 wherein said housing comprises a top housing section, a middle housing section attached to said top housing section and a bottom housing section attached to said middle housing section.
 16. The reamer of claim 15 comprising a wiper ring provided in said housing and encircling said shaft for cleaning said shaft.
 17. A reamer for use with a wire line and impact device in oil well tubing and casing, said reamer comprising: a housing having an upper housing end and a lower housing end; a plurality of lock nut lug seats provided in said housing between said upper housing end and said lower housing end; an elongated shaft slidably disposed in said housing, said shaft having an upper shaft end for attachment to the wire line, a lower shaft end spaced from said upper shaft end and shaft threads between said lower shaft end and said upper shaft end; a lock nut threadibly engaging said shaft threads beneath said plurality of lock nut lug seats, said lock nut having a plurality of lock nut lugs for removably engaging said plurality of lock nut lug seats; a reset spring provided in said housing, said reset spring interposed between said housing and said lower shaft end of said shaft; wherein said shaft and said shaft nut are displaced downwardly in said housing away from said plurality of lock nut lug seats when a load is applied to said shaft by operation of the impact device; and wherein said reset spring slidably and non-rotatably displaces said shaft upwardly in said housing, said lock nut lugs of said lock nut engage said lock nut lug seats of said housing, said lock nut rotates on said shaft, and said lock nut rotates said housing when a load is released from said shaft by operation of the impact device.
 18. The reamer of claim 17 wherein said housing comprises a top housing section, a middle housing section attached to said top housing section and a bottom housing section attached to said middle housing section.
 19. The reamer of claim 17 comprising a shaft nut provided on said shaft for engaging said reset spring.
 20. The reamer of claim 19 wherein said housing comprises a top housing section, a middle housing section attached to said top housing section and a bottom housing section attached to said middle housing section. 